This study used a small wearable heart rate sensor to monitor the daily autonomic function of 600 subjects from across all age groups over a prolonged period of time. The results indicated that the LF/HF ratio (Heart Rate Variability, LF: frequencies between 0.04 Hz - 0.15 Hz, HF: frequencies between 0.15 Hz - 0.4 Hz) an indicator of balance in the autonomic nervous system, tended to peak for subjects in their 40’s and decline thereafter. This conceivably may be partially due to the causes for concern and stress changing and/or declining for the group aged 50-plus. A decline in diurnal variation of autonomic nervous activity was also exhibited in subjects aged 50 and up, showing a tendency for decline in the function of rising sympathetic nerve activity particularly in the morning. It is conceivable that this stems from a decline in the responsiveness of the autonomic nervous system. Subjects in the 50-plus group furthermore exhibited a tendency for declining variation in autonomic nervous activity between sleeping and waking hours. This phenomenon was consistent with the tendency for there to be a rise in wake after sleep onset coupled with a decline in slow-wave sleep in middle- to old-age.
Having breached the threshold of being a hyper-aging society, the prevalence of lifestyle-related diseases and soaring medical costs have emerged as issues of dire consequence in Japan. Modern-day society, in particular, is referred to as a “stress society” and according to statistics from the Health, Labour, and Welfare Ministry [
It is said that this kind of stress suffered by many Japanese people is closely related to autonomic nervous function [
In 1921 Langley, a physiologist at the University of Cambridge, published “Autonomic Nervous System” and classified the autonomic nervous system into three systems: sympathetic nerves, parasympathetic nerves, and enteric nerves, establishing the current concept of autonomic nerves [
The sympathetic nerves together with parasympathetic nerves form the autonomic nervous system, and are the nerves that control the secretory glands, blood vessels, internal organs, and so on. During mental stimulation or exercise, they work to increase the activity of the whole body, such as secreting saliva, increasing blood pressure/blood sugar, constricting blood vessels in the skin and internal organs, and collecting blood in the muscles/brain [
On the other hand, the parasympathetic nerves emanate from the brain region and the sacral region and, mainly through the vagus nerve, secrete acetylcholine as a neurotransmitter. It acts to suppress the heart and excite the gastrointestinal tract. It also acts to promote bile secretion, promote secretion of tears and saliva, dilate the pupils, etc. These autonomic nervous functions are affected not only by physical stress but also by psychological stress [
Traditionally, evaluation based on subjective values has been used as the means for quantifying stress. The Beck Depression Inventory (BDI) developed by Beck et al. [
Meanwhile, there are measurement methods using saliva, blood, and brain waves to evaluate stress based on objective values. Regarding saliva, it is possible to measure substances such as cortisol, which is an indicator of endocrine activity, SIgA, which is an indicator of immune activity, and α-amylase, which is an indicator of sympathetic nerve activity, and all of these are known to reflect states of acute and chronic stress [
Regarding blood, it is said that cytokines are produced in the brain when under stress, and cytokines are produced from the immune cells in the blood through acceleration of the hypothalamus and autonomic nerves. There are reports that patients with depression have increased levels of such cytokines [
Regarding brain waves, the term alpha waves refers to the 8 - 13 Hz component of the electrical signal (brain waves) generated by the human or animal brain, and in the brain waves at the time of relaxation or when the eyes are closed, the proportion occupied by alpha waves is higher than that of other frequency components. They decrease when the eyes are open or during visual stimulation, physical exercise, or mental activity such as arithmetic memorization, or when nervous or asleep. At the present time, it has been found that alpha waves increase when relaxing [
However, these objective indices are, in the case of saliva measurement, time-consuming to collect and evaluate, and in the case of blood measurement, they are invasive, so there is a considerable physical burden on the test subject. Also, in the case of brain wave measurement, it is necessary to mount electrodes in multiple places, and it becomes a large-scale measurement. Therefore, it is difficult to evaluate stress easily using these methods, and they are not suitable for obtaining long-term data from a large number of test subjects.
Therefore, heart rate variability analysis can be included as a method for evaluating autonomic nervous function more simply and non-invasively. In recent years, it has become possible to measure the fluctuation of the heartbeat (interval between heartbeats) by using a small wearable heart rate sensor that can be worn in everyday life, and use heart rate variability analysis to calculate the indices of sympathetic nerve activity and parasympathetic nerve activity.
Generally, there is fluctuation of the heartbeat in a living body, and when this fluctuation is frequency analyzed, a peak can be seen at a certain frequency. In the case of a person, there appear a high frequency component (0.15 - 0.40 Hz: HF) reflecting the variation of the respiratory cycle and a low frequency component (0.05 - 0.15 Hz: LF) reflecting fluctuation in blood pressure, both of which reflect autonomic nerve activity. It is said that HF is regulated by the parasympathetic nerves, and LF is regulated by both sympathetic and parasympathetic nerves [
There are several prior studies of the relationship between autonomic nervous indices and physiological phenomena that used such heart rate variability analysis.
Previous research has explored the relationship between the severity of depression based upon the SDS (“Self-rating Depression Scale”) and autonomic activity obtained by analyzing heart rate variability from a Holter ECG monitor in 31 subjects (12 males and 19 females) diagnosed with mood disorders. In association with the severity of depression, the results demonstrated a significant rise in sympathetic nerve function along with significantly diminishing parasympathetic nerve function. Accordingly, in assessments of depression severity conducted with the use of Holter ECG monitors, these results support the onset of abnormalities in autonomic nerve function brought on by depression [
In another paper examining the effects of depression on the autonomic nervous system in 16 male subjects diagnosed with mild heart attacks, a trend was observed of elevated sympathetic nerve function and suppressed parasympathetic nerve function as subjects’ scores rose on the SDS (denoting increasingly severe depression) [
Also, in the Multiethnic Study of Atherosclerosis (MESA), a leading epidemiological study in the United States, as a result of investigating the relationship between depression symptoms, anger, anxiety, social support scores and parasympathetic nerve functions, evaluated in questionnaire form, it was observed that there was a significant negative association with symptoms of depression. Therefore, it is said that continuing depression in particular affects autonomic nervous function, especially parasympathetic function [
In addition to those people who have specific diseases as described above, there are several reports that the balance of the autonomic nervous system also changes with age. This is because the internal environment of the human body is kept constant by the homeostasis mechanism, but with age the balance of the autonomic nervous system deteriorates, so it is said to become difficult for the body to respond appropriately to changes in the external environment. In previous reports, a gradual decline in parasympathetic function due to aging in females and predominance of sympathetic function due to aging in males have been recognized, but many reports are based on the results of short-term measurement [
Consequently, in this study we used a small wearable heart rate sensor capable of long-term monitoring to test how age-related changes in levels of autonomic activity and diurnal variations in the autonomic nerves change as a function of age. We also attempt to reveal variations across age groups, diurnal variations, and variations between sleeping and waking states by monitoring a large pool of subjects ranging across all age groups as they went about their daily lives.
In this study, we measured biological data from 600 subjects (329 males, 271 females) for a prolonged period of time (24 hours)using a small wearable heart rate sensor (WHS-1) produced by Union Tool Co., shown in
The small wearable heart rate sensor can measure RR intervals, body surface temperature, and triaxial acceleration. The sensor’s sampling frequency for heart-rate intervals, body surface temperature, and triaxial acceleration is 1000 Hz, 1 Hz, and 31.25 Hz, respectively.
Fast Fourier Transform (FFT) was used for the frequency analysis of the measured RR intervals, defining the low-frequency component (LF) as the
Age | Man | Female | Total |
---|---|---|---|
10’s | 26 | 23 | 49 |
20’s | 59 | 39 | 98 |
30’s | 95 | 47 | 142 |
40’s | 77 | 87 | 164 |
50’s | 37 | 44 | 81 |
Over 60’s | 35 | 31 | 66 |
Total | 329 | 271 | 600 |
frequencies between 0.04 Hz - 0.15 Hz and the high-frequency component (HF) as the frequencies between 0.15 Hz - 0.4 Hz. The sum of the LF and HF components is referred to as total power (TP), and is considered to be an indicator of overall autonomic nervous activity. Our method for computing indicators of autonomic nerve activity adhered to procedures from paper [
In this experiment, we use solely the data where subjects exhibit little body movement from among the long-term measurement data. To analyze the data, body movement levels were determined on the basis of the acceleration sensors embedded in the small wearable heart rate sensor using the supplied software (produced by WINFrontier Co.). It has been reported that, in general, the composite value of triaxial acceleration correlates to body activity indicators and energy consumption, and the values change while walking, running, and resting [
The threshold for the composite value of acceleration was configured in alignment with each of the activities (walking, running, resting) on the sensor to distinguish the activity. Only the data determined as being recorded at rest when there is little body movement was used. IBM SPSS Statistics Version 22 was used for statistical processing in this study, with the level of statistical significance being 5%. We used the games-howell method for multiple comparison.
We investigated the relationship between age and the LF component of the autonomic nerve indicators. It is said that the LF component is a low frequency component (0.05 - 0.15 Hz) of heart rate variability analysis and is regulated by both sympathetic and parasympathetic nerves [
Subjects were divided into six groups from teenagers to subjects aged 60-plus and the Games-Howell method was used to conduct multiple comparisons in order to examine the variances between groups. The results are shown in
Subsequently, the HF component was studied. Since the HF component is considered to be the high frequency component (0.15 - 0.40 Hz) of heart rate variability analysis and disappears with a parasympatholytic drug (atropine: 0.04 mg/kg), the cardiac vagus nerve is thought to be involved, and is said to display parasympathetic nervous activity [
The Games-Howell method was used to conduct multiple comparisons to examine the variances between the groups. The results are shown in
Next, we investigated the relationship between total power (TP), an indicator of the autonomic nerves, and age. Total power is the sum of the LF and HF components and is considered to be an indicator representative of the volume of autonomic nerve activity [
The subjects were divided into six groups from teenagers to subjects aged 60-plus, and the Games-Howell method was used to conduct multiple comparisons in order to examine the variances between groups. The results are shown in
Earlier studies also showed a tendency for LF, HF, and total power to decrease with aging [
Finally, we examine the relationship between age and the LF/HF ratio, an indicator of the autonomic nerves. The LF/HF ratio is considered to be an indicator of the balance between the sympathetic and parasympathetic nerves, or an
Dependent variable: LF (ms2) | ||||||
---|---|---|---|---|---|---|
Games-Howell | ||||||
(I) Age flag | (J) Age flag | Mean difference (I-J) | Std. error | Sig. | 95% Confidence interval | |
Lower bound | Upper bound | |||||
10’s | 20’s | −0.112159369* | 0.0140548007 | 0.000 | −0.152218228 | −0.072100510 |
30’s | 0.0120527425 | 0.0137553960 | 0.952 | −0.027153352 | 0.0512588369 | |
40’s | 0.316947065* | 0.136172453 | 0.000 | 0.2781344368 | 0.3557596934 | |
50’s | 0.576613248* | 0.0136477862 | 0.000 | 0.5377136369 | 0.6155128598 | |
Over 60’s | 0.646600454* | 0.0138285632 | 0.000 | 0.6071859647 | 0.6860149426 | |
20’s | 10’s | 0.112159369* | 0.0140548007 | 0.000 | 0.0721005100 | 0.1522182285 |
30’s | 0.124212112* | 0.0050304089 | 0.000 | 0.4098767908 | 0.1385474326 | |
40’s | 0.429106434* | 0.0046393388 | 0.000 | 0.4158855298 | 0.4423273389 | |
50’s | 0.688772618* | 0.0047282304 | 0.000 | 0.6752983878 | 0.7022468475 | |
Over 60’s | 0.758772618* | 0.0052271649 | 0.000 | 0.7438637352 | 0.7736559105 | |
30’s | 10’s | −0.01205742 | 0.0137553960 | 0.952 | −0.051258837 | 0.0271533519 |
20’s | −0.124212112* | 0.0050304089 | 0.000 | −0.138547433 | −0.109876791 | |
40’s | 0.304894323* | 0.0036327621 | 0.000 | 0.2945419477 | 0.3152466975 | |
50’s | 0.564560506* | 0.0037456186 | 0.000 | 0.55388647914 | 0.5452345204 | |
Over 60’s | 0.634547711* | 0.0043585260 | 0.000 | 0.6221269835 | 0.6469684388 | |
40’s | 10’s | −0.316947065* | 0.0136172453 | 0.000 | −0.355759693 | −0.278134437 |
20’s | −0.429106434* | 0.0046393388 | 0.000 | −0.442327339 | −0.415885530 | |
30’s | −0.304894323* | 0.0036327621 | 0.000 | −0.315246697 | −0.294541948 | |
50’s | 0.259666193* | 0.0032012668 | 0.000 | −0.2505434069 | 0.2687889597 | |
Over 60’s | 0.329653389 | 0.0039006665 | 0.000 | −0.3185373741 | 0.3107694029 | |
50’s | 10’s | −0.546613248* | 0.0136477862 | 0.000 | −0.614412860 | −0.537713637 |
20’s | −0.688772618* | 0.0047282304 | 0.000 | −0.702246847 | −0.575298388 | |
30’s | −0.564560506* | 0.0037456186 | 0.000 | −0.575234520 | −0.553886491 | |
40’s | −0.259666183* | 0.0032012668 | 0.000 | −0.268788960 | −0.250543407 | |
Over 60’s | 0.069987205* | 0.0040059828 | 0.000 | 0.0585710597 | 0.0814033508 | |
Over 60’s | 10’s | −0.646600454* | 0.0138285632 | 0.000 | −0.686014943 | −0.607185965 |
20’s | −0.758459823* | 0.0052271649 | 0.000 | −0.773655911 | −0.743863735 | |
30’s | −0.634547711* | 0.0043585260 | 0.000 | −0.646968439 | −0.622126983 | |
40’s | −0.329653389* | 0.0039006665 | 0.000 | −0.340769403 | −0.318537374 | |
50’s | −0.069987205* | 0.0040059828 | 0.000 | −0.081403351 | −0.508571060 |
*The mean difference is significant at the 0.05 level.
(I) Age flag | (J) Age flag | Mean difference (I-J) | Std. error | Sig. | 95% Confidence interval | |
---|---|---|---|---|---|---|
Lower bound | Upper bound | |||||
10’s | 20’s | 0.0012325036 | 0.0098947422 | 1.000 | −0.026969272 | 0.0294342789 |
30’s | 0.137519813' | 0.0095776040 | 0.000 | 0.1102213130 | 0.1648183128 | |
40’s | 0.310538135* | 0.0094768242 | 0.000 | 0.2835266626 | 0.3375496078 | |
50’s | 0.400229014* | 0.0094902572 | 0.000 | 0.3731792839 | 0.4272787447 | |
Over 60’s | 0.346629397* | 0.0096120152 | 0.000 | 0.3192328882 | 0.3740259052 | |
20’s | 10’s | −0.001232504 | 0.0098947422 | 1.000 | −0.029434279 | 0.0269692717 |
30’s | 0.136287309* | 0.0035862520 | 0.000 | 0.1260674358 | 0.1465071828 | |
40’s | 0.309305632* | 0.0033077032 | 0.000 | 0.2998795191 | 0.3187317442 | |
50’s | 0.398996511* | 0.0033459955 | 0.000 | 0.3894612762 | 0.4085317452 | |
Over 60’s | 0.345396893* | 0.0036771648 | 0.000 | 0.3349179180 | 0.3558758682 | |
30’s | 10’s | −0.137519813" | 0.0095776040 | 0.000 | −0.164818313 | −0.110221313 |
20’s | −0.136287309' | 0.0035862520 | 0.000 | −0.146507183 | −0.126067436 | |
40’s | 0.173018322* | 0.0021829970 | 0.000 | 0.1667973767 | 0.1792392680 | |
50’s | 0.262709201* | 0.0022405938 | 0.000 | 0.2563241089 | 0.2690942939 | |
Over 60’s | 0.209109584* | 0.0027103720 | 0.000 | 0.2013856925 | 0.2168334751 | |
40’s | 10’s | −0.310538135' | 0.0094768242 | 0.000 | −0.337549608 | −0.283526663 |
20’s | −0.309305632* | 0.0033077032 | 0.000 | −0.318731744 | −0.299879519 | |
30’s | −0.173018322* | 0.0021829970 | 0.000 | −0.179239268 | −0.166797377 | |
50’s | 0.089690879* | 0.0017606697 | 0.000 | 0.0846734292 | 0.0947083290 | |
Over 60’s | 0.036091261' | 0.0023293375 | 0.000 | 0.0294531592 | 0.0427293637 | |
50’s | 10’s | −0.400229014' | 0.0094902572 | 0.000 | −0.427278745 | −0.373179284 |
20’s | −0.398996511' | 0.0033459955 | 0.000 | −0.408531745 | −0.389461276 | |
30’s | −0.262709201' | 0.0022405938 | 0.000 | −0.269094294 | −0.256324109 | |
40’s | −0.089690879' | 0.0017606697 | 0.000 | −0.094708329 | −0.084673429 | |
Over 60’s | −0.053599618' | 0.0023834006 | 0.000 | −0.060391786 | −0.046807450 | |
Over 60’s | 10’s | −0.346629397* | 0.0096120152 | 0.000 | −0.374025905 | −0.319232888 |
20’s | −0.345396893* | 0.0036771648 | 0.000 | −0.355875868 | −0.334917918 | |
30’s | −0.209109584* | 0.0027103720 | 0.000 | −0.216833475 | −0.201385692 | |
40’s | −0.036091261' | 0.0023293375 | 0.000 | −0.042729364 | −0.029453159 | |
50’s | 0.053599618' | 0.0023834006 | 0.000 | 0.0468074498 | 0.0603917855 |
*The mean difference is significant at the 0.05 level.
indicator of sympathetic nerve activity, although as mentioned earlier, interpretations are split. The subjects were divided into six groups from teenagers to subjects aged 60-plus, and the Games-Howell method was used to conduct multiple comparisons in order to examine the variances between groups. The results are shown in
Multiple comparisons Dependent variable: TP Games-Howell | ||||||
---|---|---|---|---|---|---|
Mean difference (I-J) | 95% Confidence interval | |||||
(I) Age flag | (j) Age flag | Std. error | Sig. | Lower bound | Upper bound | |
10’s | 20’s | −0.110926866* | 0.0221587508 | 0.000 | −0.174083568 | −0.047770163 |
30’s | 0.149572555* | 0.0216270603 | 0.000 | 0.0879302055 | 0.2112149052 | |
40’s | 0.627485200* | 0.0214196776 | 0.000 | 0.5664334909 | 0.6885369097 | |
50’s | 0.976842263* | 0.0214451137 | 0.000 | 0.9157181096 | 1.037966416 | |
Over 60’s | 0.993229850* | 0.0217387010 | 0.000 | 0.9312695297 | 1.055190171 | |
20’s | 10’s | 0.110926866* | 0.0221587508 | 0.000 | 0.0477701630 | 0.1740835683 |
30’s | 0.260499421* | 0.0076507554 | 0.000 | 0.2386968006 | 0.2823020414 | |
40’s | 0.738412066' | 0.0070432171 | 0.000 | 0.7183407143 | 0.7584834177 | |
50’s | 1.08776913* | 0.0071201982 | 0.000 | 1.067478395 | 1.108059862 | |
Over 60’s | 1.10415672* | 0.0079608695 | 0.000 | 1.081470275 | 1.126843157 | |
30’s | 10’s | −0.149572555* | 0.0216270603 | 0.000 | −0.211214905 | −0.087930206 |
20’s | −0.260499421* | 0.0076507554 | 0.000 | −0.282302041 | −0.238696801 | |
40’s | 0.477912645* | 0.0051309270 | 0.000 | 0.4632909081 | 0.4925343818 | |
50’s | 0.827269707* | 0.0052360984 | 0.000 | 0.8123482271 | 0.8421911876 | |
Over 60’s | 0.843657295' | 0.0063320570 | 0.000 | 0.8256124836 | 0.8617021062 | |
40’s | 10’s | −0.627485200* | 0.0214196776 | 0.000 | −0.688536910 | −0.566433491 |
20’s | −0.738412066* | 0.0070432171 | 0.000 | −0.758483418 | −0.718340714 | |
30’s | −0.477912645* | 0.0051309270 | 0.000 | −0.492534382 | −0.463290908 | |
50’s | 0.34935706* | 0.0042999506 | 0.000 | 0.3371033265 | 0.3616107982 | |
Over 60’s | 0.365744650* | 0.0055828125 | 0.000 | 0.3498348727 | 0.3816544272 | |
50’s | 10’s | −0.976842263* | 0.0214451137 | 0.000 | −1.03796642 | −0.915718110 |
20’s | −1.08776913* | 0.0071201982 | 0.000 | −1.10805986 | −1.06747839 | |
30’s | −0.827269707* | 0.0052360984 | 0.000 | −0.842191188 | −0.812348227 | |
40’s | −0.349357062* | 0.0042999506 | 0.000 | −0.361610798 | −0.337103327 | |
Over 60’s | 0.016387588* | 0.0056796224 | 0.045 | 0.0002019182 | 0.0325732570 | |
Over 60’s | 10’s | −0.993229850* | 0.0217387010 | 0.000 | −1.05519017 | −0.931269530 |
20’s | −1.10415672* | 0.0079608695 | 0.000 | −1.12684316 | −1.08147028 | |
30’s | −0.843657295* | 0.0063320570 | 0.000 | −0.861702106 | −0.825612484 | |
40’s | −0.365744650* | 0.0055828125 | 0.000 | −0.381654427 | −0.349834873 | |
50’s | −0.016387588* | 0.0056796224 | 0.045 | −0.032573257 | −0.000201918 |
*The mean difference is significant at the 0.05 level.
Multiple comparisons Dependent variable: LF/HF Games-Howell | ||||||
---|---|---|---|---|---|---|
Mean difference (I-J) | 95% Confidence interval | |||||
(I) Age flag | (J) Age flag | Std. error | Sig. | Lower bound | Upper bound | |
10’s | 20’s | −0.518237016* | 0.0279154228 | 0.000 | −0.597800398 | −0.438673634 |
30’s | −0.832669919* | 0.0277558174 | 0.000 | −0.911778684 | −0.753561154 | |
40’s | −1.07084570* | 0.0280485861 | 0.000 | −1.15078837 | −0.990903024 | |
50’s | −0.747990162* | 0.0300676722 | 0.000 | −0.833684432 | −0.662295891 | |
Over 60’s | 0.604431896* | 0.0288130236 | 0.000 | 0.5223116679 | 0.6865521250 | |
20’s | 10’s | 0.518237016* | 0.0279154228 | 0.000 | 0.4386736344 | 0.5978003984 |
30’s | −0.314432902* | 0.0131144537 | 0.000 | −0.351805533 | −0.277060272 | |
40’s | −,552608683* | 0.0137232167 | 0.000 | −0.591716104 | −0.513501262 | |
50’s | −0.229753145* | 0.0174833751 | 0.000 | −0.279576482 | −0.179929809 | |
Over 60’s | 1.12266891* | 0.0152247767 | 0.000 | 1.079281900 | 1.166055925 | |
30’s | 10’s | 0.832669919* | 0.0277558174 | 0.000 | 0.7535611539 | 0.9117786837 |
20’s | 0.314432902* | 0.0131144537 | 0.000 | 0.2770602722 | 0.3518055326 | |
40’s | −0.238175780* | 0.0133955682 | 0.000 | −0.276349449 | −0.200002112 | |
50’s | 0.084679757* | 0.0172273902 | 0.000 | 0.0355858975 | 0.1337736169 | |
Over 60’s | 1.43710182* | 0.0149301170 | 0.000 | 1.394554496 | 1.479649135 | |
40’s | 10’s | 1.07084570* | 0.0280485861 | 0.000 | 0.9909030245 | 1.150788374 |
20’s | 0.552608683* | 0.0137232167 | 0.000 | 0.5135012615 | 0.5917161041 | |
30’s | 0.238175780* | 0.0133955682 | 0.000 | 0.2000021120 | 0.2763494489 | |
50’s | 0.322855538* | 0.0176952184 | 0.000 | 0.2724285569 | 0.3732825184 | |
Over 60’s | 1.67527760* | 0.0154675847 | 0.000 | 1.631198717 | 1.719356475 | |
50’s | 10’s | 0.747990162* | 0.0300676722 | 0.000 | 0.6622958908 | 0.8336844324 |
20’s | 0.229753145* | 0.0174833751 | 0.000 | 0.1799298088 | 0.2795764816 | |
30’s | −,084679757* | 0.0172273902 | 0.000 | −0.133773617 | −0.035585897 | |
40’s | −0.322855538* | 0.0176952184 | 0.000 | −0.373282518 | −0.272428557 | |
Over 60’s | 1.35242206* | 0.0188835352 | 0.000 | 1.298608520 | 1.406235596 | |
Over 60’s | 10’s | −0.604431896* | 0.0288130236 | 0.000 | −00.686552125 | −0.522311668 |
20’s | −1.12266891* | 0.0152247767 | 0.000 | −1.16605593 | −1.07928190 | |
30’s | −1.43710182* | 0.0149301170 | 0.000 | −1.47964913 | −1.39455450 | |
40’s | −1.67527760* | 0.0154675847 | 0.000 | −1.71935647 | −1.63119872 | |
50’s | −1.35242206* | 0.0188835352 | 0.000 | −1.40623560 | −1.29860852 |
*The mean difference is significant at the 0.05 level.
LF/HF ratio to peak in the 40s and trend downward thereafter.
In previous studies by Zhang et al. [
In addition, looking at the Ministry of Health, Labor and Welfare statistics shown in
Also, in the Ministry of Health, Labor and Welfare statistics shown in
In this section, we analyzed the relationship between the autonomic nerve indicator LF/HF ratio and diurnal variations in order to assess the relationship between autonomic nerve function and diurnal variations. The analysis divided one day into eight three-hour sections.
show the aggregate results for subjects aged 50-plus.
Comparing the diurnal variations of the LF/HF ratio for subjects below 50 against subjects aged 50-plus reveals striking differences in the elevation rates of the LF/HF ratio from between 3:00 and 6:00 in the morning to between 6:00 and 9:00 in the morning.
Descriptives LFHF | ||||||||
---|---|---|---|---|---|---|---|---|
N | Mean | Std. deviation | Std. error | 95% Confidence interval for mean | Minimum | Maximum | ||
Lower bound | upper bound | |||||||
0:00-3:00 | 67,836 | 2.393469930 | 2.863404234 | 0.0109939194 | 2.371921866 | 2.415017993 | 0.0207066132 | 50.54979966 |
3:00-6:00 | 64,337 | 2.020522403 | 2.419858802 | 0.0095402471 | 2.001823516 | 2.039221289 | 0.0310185554 | 71.04799683 |
6:00-9:00 | 59,273 | 3.573768236 | 3.883893100 | 0.0159528695 | 3.542500558 | 3.605035915 | 0.0536916576 | 69.86762657 |
9:00-12:00 | 75,585 | 3.835712749 | 3.256889566 | 0.0118463681 | 3.812493930 | 3.858931568 | 0.0150149330 | 56.80034183 |
12:00-15:00 | 74,545 | 4.048507535 | 3.558050522 | 0.0130317533 | 4.022965361 | 4.074049709 | 0.0806316874 | 60.71608144 |
15:00-18:00 | 75,799 | 3.916584321 | 3.440740240 | 0.0124974138 | 3.892089457 | 3.941079185 | 0.0541924435 | 60.96557143 |
18:00-21:00 | 68,882 | 4.094753570 | 3.621127728 | 0.0137972003 | 4.067711088 | 4.121796053 | 0.0466757865 | 58.15724576 |
21:00-24:00 | 63,486 | 3.720298319 | 3.975522798 | 0.0157781204 | 3.689373191 | 3.751223446 | 0.0382549455 | 124.3444459 |
Total | 549,743 | 3.476204212 | 3.483718151 | 0.0046985425 | 3.466995221 | 3.485413204 | 0.0150149330 | 124.3444459 |
Looking at the standard deviation of the average value of LF/HF in each time period, it is 0.739 for those under 50 years old, but it is 0.419 for those 50 years old and above, and the trend is for the fluctuation of autonomic nervous function to decrease in the elderly.
Sympathetic nerve activity should become vigorous in the morning in preparation for activity during the day because of human circadian rhythms; however, this switch is faint for subjects aged 50 and up. In other words, this may indicate the possibility of a decline in responsiveness of the autonomic nerves and a drop off in adaptability to the external environment.
There are several previous studies on the decline in responsiveness of the autonomic nervous system with aging, and when healthy people of different generations were examined using the orthostatic hypotension test, the deep breath test, and the perspiration reaction, the average reaction amount statistically significantly decreased as the age group increased, and the response of the autonomic nerves to changes in the environmental or the body tended to be slower [
Thus, the tendency of LF/HF in this study appears the same as the trend for autonomic nerves to change with age seen in previous studies, and a tendency was seen that suggests a decrease in responsiveness with aging.
Next, we analyzed the relationship between the autonomic nerve indicator LF/HF ratio while sleeping and waking.
Comparing the variations while sleeping and waking of the LF/HF ratio for subjects under 50 and subjects aged 50 and up, although both groups exhibit significant differences while sleeping and while waking, the variations between
Multiple comparisons Dependent variable: LFHF Games-Howell | ||||||
---|---|---|---|---|---|---|
(I) Time flag | (J) Time flag | Mean | Std. error | Sig. | 95% Confidence interval | |
Difference (I-J) | Lower bound | Upper bound | ||||
0:00-3:00 | 3:00-6:00 | 0.372947527* | 0.0145562 | 0 | 0.3288288 | 0.4170663 |
6:00-9:00 | −1.18029831* | 0.0193742 | 0 | −1.2390204 | −1.1215763 | |
9:00-12:00 | −1.44224282* | 0.0161618 | 0 | −1.4912279 | −1.3932577 | |
12:00-15:00 | −1.65503761* | 0.0170497 | 0 | −1.706714 | −1.6033612 | |
15:00-18:00 | −1.52311439* | 0.0166449 | 0 | −1.5735637 | −1.4726651 | |
18:00-21:00 | −1.70128364* | 0.0176417 | 0 | −1.7547543 | −1.647813 | |
21:00-24:00 | −1.32682839* | 0.0192306 | 0 | −1.385115 | −1.2685418 | |
3:00-6:00 | 0:00-3:00 | −0.372947527* | 0.0145562 | 0 | −0.4170663 | −0.3288288 |
6:00-9:00 | −1.55324583* | 0.0185879 | 0 | −1.6095848 | −1.4969069 | |
9:00-12:00 | −1.81519035* | 0.0152103 | 0 | −1.8612916 | −1.7690891 | |
12:00-15:00 | −2.02798513* | 0.0161506 | 0 | −2.0769365 | −1.9790337 | |
15:00-18:00 | −1.89606192* | 0.0157226 | 0 | −1.9437161 | −1.8484077 | |
18:00-21:00 | −2.0742311 | 0.0167744 | 0 | −2.1250731 | −2.0233892 | |
21:00-24:00 | −1.69977592* | 0.0184382 | 0 | −1.7556609 | −1.643891 | |
6:00-9:00 | 0:00-3:00 | 1.18029831* | 0.0193742 | 0 | 1.1215762 | 1.2390204 |
3:00-6:00 | 1.55324583* | 0.0185879 | 0 | 1.4969069 | 1.6095848 | |
9:00-12:00 | −0.261944513* | 0.0198703 | 0 | −0.3221702 | −0.2017188 | |
12:00-15:00 | −0.474739299* | 0.020599 | 0 | −0.5371736 | −0.412305 | |
15:00-18:00 | −0.342816085* | 0.0202652 | 0 | −0.4042386 | −0.2813936 | |
18:00-21:00 | −0.520985334* | 0.0210916 | 0 | −0.5849126 | −0.4570581 | |
21:00-24:00 | −0.146530082* | 0.0224375 | 0 | −0.2145367 | −0.0785234 | |
9:00-12:00 | 0:00-3:00 | 1.44224282* | 0.0161618 | 0 | 1.3932577 | 1.4912279 |
3:00-6:00 | 1.81519035* | 0.0152103 | 0 | 1.7690891 | 1.8612916 | |
6:00-9:00 | 0.261944513* | 0.0198703 | 0 | 0.2017188 | 0.3221702 | |
12:00-15:00 | −0.212794786* | 0.0176114 | 0 | −0.2661737 | −0.1594159 | |
15:00-18:00 | −0.080871572* | 0.0172198 | 0 | −0.1330635 | −0.0286797 | |
18:00-21:00 | −0.259040821* | 0.0181851 | 0 | −0.3141586 | −0.203923 | |
21:00-24:00 | 0.115414430’ | 0.0197303 | 0 | 0.0556132 | 0.1752157 | |
12:00-15:00 | 0:00-3:00 | 1.65503761* | 0.0170497 | 0 | 1.6033612 | 1.706714 |
3:00-6:00 | 2.02798513* | 0.0161506 | 0 | 1.9790337 | 2.0769365 | |
6:00-9:00 | 0.474739299* | 0.020599 | 0 | 0.412305 | 0.5371736 | |
9:00-12:00 | 0.212794786’ | 0.0176114 | 0 | 0.1594159 | 0.2661737 | |
15:00-18:00 | 0.131923214* | 0.0180558 | 0 | 0.0771975 | 0.1866489 | |
18:00-21:00 | −0.046246 | 0.0189787 | 0.224 | −0.1037689 | 0.0112768 | |
21:00-24:00 | 0.328209216* | 0.020464 | 0 | 0.2661843 | 0.3902342 | |
15:00-18:00 | 0:00-3:00 | 1.52311439* | 0.0166449 | 0 | 1.4726651 | 1.5735637 |
3:00-6:00 | 1.89606192* | 0.0157226 | 0 | 1.8484077 | 1.9437161 | |
---|---|---|---|---|---|---|
6:00-9:00 | 0.342816085* | 0.0202652 | 0 | 0.2813936 | 0.4042386 | |
9:00-12:00 | 0.080871572* | 0.0172198 | 0 | 0.0286797 | 0.1330635 | |
12:00-15:00 | −0.131923214* | 0.0180558 | 0 | −0.1866489 | −0.0771975 | |
18:00-21:00 | −0.178169249* | 0.0186158 | 0 | −0.2345923 | −0.1217462 | |
21:00-24:00 | 0.196286002* | 0.020128 | 0 | 0.1352796 | 0.2572924 | |
18:00-21:00 | 0:00-3:00 | 1.70128364* | 0.0176417 | 0 | 1.647813 | 1.7547543 |
3:00-6:00 | 2.07423117* | 0.0167744 | 0 | 2.0233892 | 2.1250731 | |
6:00-9:00 | 0.520985334* | 0.0210916 | 0 | 0.4570581 | 0.5849126 | |
9:00-12:00 | 0.259040821* | 0.0181851 | 0 | 0.203923 | 0.3141586 | |
12:00-15:00 | 0.046246 | 0.0189787 | 0.224 | −0.0112768 | 0.1037689 | |
15:00-18:00 | 0.178169249* | 0.0186158 | 0 | 0.1217462 | 0.2345923 | |
21:00-24:00 | 0.374455252* | 0.0209598 | 0 | 0.3109277 | 0.4379828 | |
21:00-24:00 | 0:00-3:00 | 1.32682839* | 0.0192306 | 0 | 1.2685417 | 1.385115 |
3:00-6:00 | 1.69977592* | 0.0184382 | 0 | 1.643891 | 1.7556608 | |
6:00-9:00 | 0.146530082* | 0.0224375 | 0 | 0.0785234 | 0.2145367 | |
9:00-12:00 | −0.115414430* | 0.0197303 | 0 | −0.1752157 | −0.0556132 | |
12:00-15:00 | −0.328209216* | 0.020464 | 0 | −0.3902342 | −0.2661843 | |
15:00-18:00 | −0.196286002* | 0.020128 | 0 | −0.2572924 | −0.1352796 | |
18:00-21:00 | −0.374455252* | 0.0209598 | 0 | −0.4379828 | −0.3109277 |
*The mean difference is significant at the 0.05 level.
waking and sleeping decline markedly for subjects aged 50-plus relative to subjects under 50. This supports the trends of previous research indicating growth in sleep time occupied by wake after sleep onset and declining levels of slow-
Descriptives LFHF | ||||||||
---|---|---|---|---|---|---|---|---|
N | Mean | Std. deviation | Std. error | 95% Confidence interval for mean | Minimum | Maximum | ||
Lower bound | Upper bound | |||||||
0:00-3:00 | 17,108 | 2.380588839 | 3.069294877 | 0.0234659961 | 2.334593077 | 2.426584600 | 0.0052378176 | 51.12275387 |
3:00-6:00 | 17,066 | 2.411597093 | 2.897219037 | 0.0221776466 | 2.368126621 | 2.455067564 | 0.0085205484 | 40.38270518 |
6:00-9:00 | 15,535 | 3.197607645 | 3.417184907 | 0.0274165530 | 3.143868002 | 3.251347289 | 0.0078901472 | 49.81408403 |
9:00-12:00 | 18,385 | 3.182214489 | 3.011838897 | 0.0222126268 | 3.138675674 | 3.225753304 | 0.0316005655 | 31.97811159 |
12:00-15:00 | 18,928 | 3.211938122 | 3.175350653 | 0.0230801872 | 3.166698893 | 3.257177351 | 0.0651674696 | 64.45880871 |
15:00-18:00 | 18,440 | 3.339790544 | 3.341343045 | 0.0246059766 | 3.291560550 | 3.388020538 | 0.0520169243 | 44.92429550 |
18:00-21:00 | 17,843 | 3.492774616 | 3.688529619 | 0.0276133653 | 3.438649742 | 3.546899489 | 0.0141719790 | 44.61341598 |
21:00-24:00 | 16,892 | 2.531507033 | 2.883233297 | 0.0221839689 | 2.488024137 | 2.574989929 | 0.0100680885 | 43.78371076 |
Total | 140,197 | 2.978154844 | 3.223821687 | 0.0086099703 | 2.961279472 | 2.995030216 | 0.0052378176 | 64.45880871 |
wave sleep in middle- to old-age [
Also, just as changes in autonomic nervous system and endocrine system rhythms, such as reduced secretion of melatonin and cortisol, are reported to be
Multiple comparisons Dependent variable: LFHF Games-Howell | ||||||
---|---|---|---|---|---|---|
(1) Time flag | (j) Time flag | Mean difference (I-J) | Std. error | Sig. | 95% Confidence interval | |
Lower bound | Upper bound | |||||
0:00-3:00 | 3:00-6:00 | −0.031008254 | 0.0322877838 | 0.980 | −0.128874716 | 0.0668582088 |
6:00-9:00 | −0.817018806' | 0.0360876758 | 0.000 | −0.926403592 | −0.707634021 | |
9:00-12:00 | −0.801625650' | 0.0323118208 | 0.000 | −0.899564774 | −0.703686527 | |
12:00-15:00 | −0.831349283' | 0.0329142525 | 0.000 | −0.931114302 | −0.731584265 | |
15:00-18:00 | −0.959201705* | 0.0340015743 | 0.000 | −1.06226252 | −0.856140894 | |
18:00-21:00 | −1.11218578’ | 0.0362374242 | 0.000 | −1.22202383 | −1.00234773 | |
21:00-24:00 | −0.150918195* | 0.0322921267 | 0.000 | −0.248797849 | −0.053038540 | |
3:00-6:00 | 0:00-3:00 | 0.0310082538 | 0.0322877838 | 0.980 | −0.066858209 | 0.1288747165 |
6:00-9:00 | −0.786010553' | 0.0352635135 | 0.000 | −0.892897413 | −0.679123692 | |
9:00-12:00 | −0.770617396’ | 0.0313886731 | 0.000 | −0.865758369 | −0.675476423 | |
12:00-15:00 | −0.800341030' | 0.0320084841 | 0.000 | −0.897360593 | −0.703321466 | |
15:00-18:00 | −0.928193451* | 0.0331255505 | 0.000 | −1.02859901 | −0.827787889 | |
18:00-21:00 | −1.08117752* | 0.0354167468 | 0.000 | −1.18852817 | −0.973826877 | |
21:00-24:00 | −0.119909941' | 0.0313683995 | 0.003 | −0.214989707 | −0.024830174 | |
6:00-9:00 | 0:00-3:00 | 0.817018806* | 0.0360876758 | 0.000 | 0.7076340211 | 0.9264035917 |
3:00-6:00 | 0.786010553' | 0.0352635135 | 0.000 | 0.6791236922 | 0.8928974129 | |
9:00-12:00 | 0.0153931562 | 0.0352855235 | 10.000 | −0.091560263 | 0.1223465749 | |
12:00-15:00 | −0.014330477 | 0.0358380024 | 10.000 | −0.122958306 | 0.0942973519 | |
15:00-18:00 | −0.142182899' | 0.0368391295 | 0.003 | −0.253845082 | −0.030520716 | |
18:00-21:00 | −0.295166970' | 0.0389122772 | 0.000 | −0.413112904 | −0.177221037 | |
21:00-24:00 | 0.666100612* | 0.0352674900 | 0.000 | 0.5592016777 | 0.7729995458 | |
9:00-12:00 | 0:00-3:00 | 0.801625650" | 0.0323118208 | 0.000 | 0.7036865267 | 0.8995647738 |
3:00-6:00 | 0.770617396’ | 0.0313886731 | 0.000 | 0.6754764234 | 0.8657583694 | |
6:00-9:00 | −0.015393156 | 0.0352855235 | 10.000 | −0.122346575 | 0.0915602626 | |
12:00-15:00 | −0.029723633 | 0.0320327307 | 0.983 | −0.126816488 | 0.0673692220 | |
15:00-18:00 | −0.157576055' | 0.0331489800 | 0.000 | −0.258052451 | −0.057099659 | |
18:00-21:00 | −0.310560127* | 0.0354386615 | 0.000 | −0.417977045 | −0.203143208 | |
21:00-24:00 | 0.650707456' | 0.0313931405 | 0.000 | 0.5555529112 | 0.7458619999 | |
12:00-15:00 | 0:00-3:00 | 0.831349283" | 0.0329142525 | 0.000 | 0.7315842652 | 0.9311143016 |
3:00-6:00 | 0.800341030* | 0.0320084841 | 0.000 | 0.7033214665 | 0.8973605926 | |
6:00-9:00 | 0.0143304770 | 0.0358380024 | 10.000 | −0.094297352 | 0.1229583059 | |
9:00-12:00 | 0.0297236331 | 0.0320327307 | 0.983 | −0.067369222 | 0.1268164883 | |
15:00-18:00 | −0.127852422’ | 0.0337364659 | 0.004 | −0.230109409 | −0.025595435 | |
18:00-21:00 | −0.280836493* | 0.0359887897 | 0.000 | −0.389920726 | −0.171752261 | |
21:00-24:00 | 0.680431089* | 0.0320128649 | 0.000 | 0.5833982183 | 0.7774639592 | |
15:00-18:00 | 0:00-3:00 | 0.959201705* | 0.0340015743 | 0.000 | 0.8561408944 | 1.062262516 |
3:00-6:00 | 0.928193451' | 0.0331255505 | 0.000 | 0.8277878894 | 1.028599013 | |
6:00-9:00 | 0.142182899* | 0.0368391295 | 0.003 | 0.0305207160 | 0.2538450818 |
9:00-12:00 | 0.157576055' | 0.0331489800 | 0.000 | 0.0570996592 | 0.2580524509 | |
---|---|---|---|---|---|---|
12:00-15:00 | 0.127852422’ | 0.0337364659 | 0.004 | 0.0255954350 | 0.2301094088 | |
18:00-21:00 | −0.152984071' | 0.0369858355 | 0.001 | −0.265090334 | −0.040877809 | |
21:00-24:00 | 0.808283511* | 0.0331297836 | 0.000 | 0.7078650920 | 0.9087019292 | |
18:00-21:00 | 0:00-3:00 | 1.11218578’ | 0.0362374242 | 0.000 | 1.002347727 | 1.222023826 |
3:00-6:00 | 1.08117752" | 0.0354167468 | 0.000 | 0.9738268772 | 1.188528169 | |
6:00-9:00 | 0.295166970* | 0.0389122772 | 0.000 | 0.1772210370 | 0.4131129037 | |
9:00-12:00 | 0.310560127' | 0.0354386615 | 0.000 | 0.2031432078 | 0.4179770453 | |
12:00-15:00 | 0.280836493* | 0.0359887897 | 0.000 | 0.1717522608 | 0.3899207260 | |
15:00-18:00 | 0.152984071' | 0.0369858355 | 0.001 | 0.0408778094 | 0.2650903336 | |
21:00-24:00 | 0.961267582" | 0.0354207061 | 0.000 | 0.8539049150 | 1.068630249 | |
21:00-24:00 | 0:00-3:00 | 0.150918195* | 0.0322921267 | 0.000 | 0.0530385404 | 0.2487978489 |
3:00-6:00 | 0.119909941' | 0.0313683995 | 0.003 | 0.0248301745 | 0.2149897072 | |
6:00-9:00 | −0.666100612* | 0.0352674900 | 0.000 | −0.772999546 | −0.559201678 | |
9:00-12:00 | −0.650707456' | 0.0313931405 | 0.000 | −0.745862000 | −0.555552911 | |
12:00-15:00 | −0.680431089' | 0.0320128649 | 0.000 | −0.777463959 | −0.583398218 | |
15:00-18:00 | −0.808283511' | 0.0331297836 | 0.000 | −0.908701929 | −0.707865092 | |
18:00-21:00 | −0.961267582" | 0.0354207061 | 0.000 | −1.06863025 | −0.853904915 |
*The mean difference is significant at the 0.05 level.
Group statistics | |||||
---|---|---|---|---|---|
Sleep flag | N | Mean | Std. deviation | Std. error mean | |
LFHF | Wake | 446,392 | 3.793270748 | 3.572033285 | 0.0053463489 |
Sleep | 103,351 | 2.106735460 | 2.671197896 | 0.0083089993 |
Levene’s test for equality of variances | t-test for equality of means | |||||||||
---|---|---|---|---|---|---|---|---|---|---|
F | Sig. | t | df | Sig. (2-tailed) | Mean difference | Std. error difference | 95% Confidence interval of the difference | |||
Lower | Upper | |||||||||
LFHF | Equal variances assured | 8745.187 | 0.000 | 142.823 | 549,741 | 0.000 | 1.686535286 | 0.0118085402 | 1.663390929 | 1.709679644 |
Equal variances not assured | 170.695 | 198,754.628 | 0.000 | 1.686535286 | 0.0098804309 | 1.667169886 | 1.705900687 |
Group statistics | |||||
---|---|---|---|---|---|
Sleep flag | N | Mean | Std. deviation | Std. error mean | |
LFHF | Wake | 109,651 | 3.145304198 | 3.252340387 | 0.0098217685 |
Sleep | 30,546 | 2.378138678 | 3.044673392 | 0.0174206172 |
Levene’s test for equality of variances | t-test for equality of means | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
F | Sig. | t | df | Sig. (2-tailed) | Mean difference | Std. error difference | 95% Confidence interval of the difference | ||||
Lower | Upper | ||||||||||
LFHF | Equal variances assured | 380.367 | 0.000 | 36.960 | 140,195 | 0.000 | 0.7671655196 | 0.020756365 | 0.7264833132 | 0.8078477260 | |
Equal variances not assured | 38.361 | 51,597.812 | 0.000 | 0.7671655196 | 0.0199986260 | 0.7279680259 | 0.8063630133 |
age-related [
Long-term monitoring of autonomic nerve function of 600 subjects across all age groups as they went about their daily lives revealed the following:
Ø The LF/HF ratio, an indicator of autonomic nerve balance, demonstrated a tendency to peak in the 40’s and decline thereafter, conceivably due partially to causes of concern and stress changing and declining for individuals aged 50-plus.
Ø Diurnal variation of autonomic nerve activity tended to decline for subjects aged 50-plus, exhibiting a tendency for a drop in rising sympathetic nerve activity function particularly in the morning, which may conceivably stem from declining responsiveness of the autonomic nervous system.
Ø Differences in autonomic nerve activity between sleeping and waking hours exhibited a tendency to decline in subjects aged 50-plus, which is consistent with the tendency for rising levels of wake after sleep onset and declining levels of slow-wave sleep in middle- to old-age.
Moving forward, we hope to examine what kind of differences emerge in these trends as well as see how the conclusions reached herein change as the result of adding correlational analysis with other biological indicators such as saliva and brain waves.
Itao, K., Komazawa, M., Luo, Z.W. and Kobayashi, H. (2017) Long-Term Monitoring and Analysis of Age-Related Changes on Autonomic Ner- vous Function. Health, 9, 323-344. https://doi.org/10.4236/health.2017.92023